The search for and recovery of oil is becoming increasingly difficult as world-wide petroleum reserves decline. In many instances, reserves trapped within certain low permeability formations, such as certain sand, carbonate, and/or shale formations, exhibit little or no production, and are thus economically undesirable to develop at current oil and gas prices. In certain unconventional formations, such as low permeability formations, the most important element that determines whether developing reservoir will be economically viable is finding sweet spots in the reservoir. It is well established that tight gas wells can become commercially viable when a sweet spot is encountered. A sweet spot is generally defined herein as the area within a reservoir that represents the best production or potential for production. Unfortunately, current technologies are unable to locate or predict when and where sweet spots exist within a given formation.
In tight reservoirs, due to low permeability of the formation, well productivity is typically low, thus making the well non-economical from a standpoint of development. Stimulation treatments are one known method that can be used to enhance well productivity and improve the economics of developing the well. One commonly employed technique for stimulating low productivity wells is hydraulic fracturing, which typically involves the injection of high viscosity fluids into the well at a sufficiently high rate so that enough pressure is built up inside the wellbore to split the formation apart. The resulting hydraulically induced fracture that is produced extends from the wellbore deep into the formation. Those of skill in the art can design the stimulation job based upon the desired height and length of the induced fracture.
Stimulation procedures can employ several techniques to insure that the induced fracture becomes conductive when injection is ceased. For example, during acid fracturing of carbonate formations, acid based fluids are injected into the formation to create an etched fracture and conductive channels, which are left open upon closure of the fracture. In use with sand or shale formations, a proppant can be included with the fracturing fluid such that the induced fracture remains propped open as it closes. These methods, however, have limited uses. For example, because shale and sandstone formations do not react with acids, acid stimulation fluids are typically not employed, and only hydraulic fracturing with proppants is employed. In carbonate formations, however, both acid fracturing fluids and proppants can be employed. These techniques, however, typically use chemicals that require extensive procedures to ensure low environmental impact to the formation and surrounding area.
Thus, additional needs exist for the ability to enhance production within a tight gas formation to enhance production thereof. Specifically, methods and compositions having low environmental impact are needed for the creation of synthetic sweet spots.